1. Field of the Invention
The present invention relates to the rigidity of a housing obtained by controlling the shape of a main chassis, serving as an internal structure, of a digital still-image camera (hereinafter abbreviated as a “digital camera”).
2. Description of the Related Art
Recently, in image pickup apparatuses, such as digital cameras or the like, that use recording media, it has become desirable intended to realize a low running cost caused by a recording/reproducing function, and a small and light apparatus. A recording-medium accommodating unit of a conventional digital camera will now be described with reference to FIG. 7.
FIG. 7 is a schematic perspective view illustrating a portion near a recording-medium accommodating unit of a conventional digital camera. This digital camera generally includes a solid-state image pickup device, image pickup means including a lens, a signal processing unit, a power supply circuit unit, and a battery accommodating unit.
In particular, FIG. 7 illustrates a compact-flash card (registered trade name; hereinafter abbreviated as a “CF card”) 101, serving as a recording medium for recording data of an object image or the like converted into an electrical signal by the solid-state image pickup device, a CF-card slot 102, serving as an accommodating portion for the CF card 101, an ejection button 103 provided at the CF-card slot 102 for taking the CF card 101 out of the camera, a front cover 104, serving as a camera-front-surface protective housing, a rear cover 105, serving as a camera-rear-surface protective housing, a CF-card cover 106 rotatably supported on the main body of the camera by a rotation shaft 106a, a rear inner member 107 made of resin and bonded to the rear cover 105, disposed between the rear cover 105 and the CF-card slot 102, and a slide button 108 fixed to the rear inner member 107 by a patching structure (not shown) so as to be vertically movable, and biased in a downward direction by an urging spring (not shown).
When a user desires to take the CF card 101 out of the camera, the user opens the CF-card cover 106 from a closed state by manually moving the slide button 108 upward against the bias force of the urging spring into to provide a state shown in FIG. 7. In this state, the ejection button 103 is extended at a position indicated by broken lines 103a. By manually pushing the ejection button 103 toward the interior of the camera, the CF card 101 is partially ejected from the camera CF slot 102, and the CF card 101 can be taken out of the camera.
Next, the internal structure of the conventional camera will be described with reference to a schematic cross-sectional view shown in FIG. 8.
A main chassis 109 serves as the internal structure of the conventional camera, and is made of a thin steel plate in order to reduce the size and weight of the camera. FIG. 8 also illustrates a battery 110, a battery chamber 111 for accommodating the battery 110, a signal processing substrate 112, a barrel 113 incorporating a solid-state image pickup device and a lens (collectively shown in phantom), a power supply circuit unit 114, and an image display unit 115.
The main chassis 109 has a substantially cornered-U-shape, with a bent portion 109a that contacts the front cover 104 and the rear cover 105. The battery chamber 111 is fixed on the main chassis 109 by conventional fixing means (not shown), and contacts the front cover 104 and the rear cover 105. The CF-card slot 102, serving as an accommodating unit for the CF card 101, is disposed in a space formed by the main chassis 109, and the rear inner member 107 boded to the rear cover 105 (for example, refer to patent literature 1).
Next, a conventional battery lock and battery chamber lid will be described with reference to FIG. 9. FIG. 9 is a schematic perspective view illustrating a portion near the battery chamber lid.
In FIG. 9, there are shown a battery chamber lid 116, and a battery lock 117 having an L-shaped pawl 117b at a distal end thereof. The battery lock 117 is rotatably supported on a shaft (not shown), and is biased by the urging force of an urging spring (not shown) so as to be rotatable in the direction of an arrow J. When the battery 110 is accommodated in the battery chamber 111, the distal end (pawl 117b) of the battery lock 117 rotates so as to cover the battery 110 by the urging spring, thereby to prevent the battery 110 from exiting the battery chamber 111. FIG. 9 illustrates a state in which the battery chamber lid 116 is open. The battery chamber lid 116 is rotated from a closed state to this opened state by first sliding the battery chamber lid 116 in the direction of an arrow K that is orthogonal to a battery insertion direction, and then rotating the battery lid 116 in the direction of an arrow L so that a travel of the distal end of the battery chamber lid 116 depicts an arc. The battery 110 then can be taken out in the direction of an arrow N, e.g., by means of a discharge spring (not shown) provided in the battery chamber 111, by manually engaging a recess 117a of the battery lock 117 so as to rotate it in the direction of an arrow M, against the elastic biasing force of the urging spring in the direction of the arrow J, thereby detaching the pawl 117b from the battery 110.
Next, a tripod mount screw to be used when mounting the camera to a tripod will be described with reference to FIGS. 10 and 11.
A tripod screw mount 118 including an internal screw thread portion 118a therein is fixed to the main chassis 109 and a bottom plate 119 using screws (not shown). By fixing the front cover 104 and the rear cover 105 (neither shown in FIGS. 10 and 11) to the tripod screw mount 118 using screws, the main body of the digital camera and the tripod screw 118 are integrated to secure rigidity that is necessary when mounting the camera to a tripod. As shown in FIG. 11, the tripod screw mount 118 includes an incomplete screw thread portion 118b in addition to the screw thread portion 118a. These portions are produced when performing tapping processing for the tripod screw mount 118 having the shape of a bag. A semispherical projection 118c having substantially the same height as the incomplete screw thread portion 118b is also included in the tripod screw mount 118.
The rigidity of the housing of the conventional digital camera having the above-described configuration is weak with regard to deflection at a central portion, and stress due to pressure on the camera from either side, because the rigid main chassis 109 and the battery chamber 111 are connected at a central portion. Since a thin steel plate is used in order to reduce the size and the weight of the camera, there is a possibility that the camera may become deformed at a connecting portion if an excess stress is applied, resulting in destruction of internal components, such as the barrel and the like.
As for the recording-medium accommodating unit, in FIG. 7, if a stress indicated by an arrow P is applied to the rear cover 105 that is not directly supported by the main chassis 109, there is a possibility that the entirety of the rear inner member 107 may become deformed because of a cantilever structure effect in which there is no support on the main body, thereby causing a stress in the CF-card slot 102, resulting in destruction of the CF card 101.